[1] Combines have been proposed that measure the weight and moisture of grains contained in a grain tank and output the measurement result as harvest information regarding the harvested grains. For example, the combine described in Patent Document 1 includes a moisture measurement apparatus for taking in some of the grains supplied to the grain tank and measuring the moisture content thereof, and a load cell for detecting a load applied to the grain tank. During traveling for harvest, harvested grains (yield) per reaping area can be calculated based on an increase in the grain tank. However, it is difficult to accurately calculate the yield in a relatively small reaping area based on a change in the load on the grain tank, because the increased weight of the grains is small compared with the weight of the grain tank itself, and a measurement error is likely to occur due to the grains being on one side in the grain tank, for example.
To more accurately calculate the yield, the combine described in Patent Document 2 includes: a yield measurement container having a yield receiving opening for receiving grains supplied to a grain tank, a yield discharge opening for discharging received grains, and a yield shutter for opening and closing the yield discharge opening; a time calculator for calculating an accumulation time required for a given volume of grain to accumulate in a yield measurement container; and a yield calculator for calculating a yield per unit of travel (yield per unit of reaping area) based on travel speed and accumulation time. By statistically processing the yield per unit of travel that is sequentially calculated by the yield calculator, a yield distribution for an entire field can also be created.
In the advanced, computer-assisted field management, the yield distribution per minute parcel of a field is important data. However, when a combine travels for harvest work, non-harvest work travel that does not involve harvest work occurs during traveling while turning and traveling around obstruction. Despite this, the aforementioned conventional combines obtain the yield per unit of travel without distinguishing between harvest work travel and non-harvest work travel. For this reason, the yield distribution for an entire field may be incorrect.
[2] Combines have been proposed that simultaneously measure the weight (yield) and moisture (taste) of grains contained in a grain tank to evaluate harvested grains. For example, the combine described in Patent Document 2 includes: a yield calculation apparatus for calculating a yield of harvested grain per unit of travel; and a taste calculation apparatus for calculating the taste of the harvested grains. The yield calculation apparatus has: a yield measurement container having a yield receiving opening for receiving grains supplied to a grain tank, a yield discharge opening for discharging received grains, and a yield shutter for opening and closing the yield discharge opening; a time calculator for calculating an accumulation time required for a given volume of grain to accumulate in a yield measurement container; and a yield calculator for calculating a yield per unit of travel (yield per unit of reaping area) based on a travel speed and the accumulation time. The taste calculation apparatus has: a taste measurement container having a taste receiving opening for receiving grains discharged from the yield discharge opening, a taste discharge opening for discharging the received grains, and a taste shutter for opening and closing the taste discharge opening; and a taste measurer for measuring a taste of grains accumulated in the taste measurement container. With this configuration, it is possible to evaluate, at any time, a distribution of the yield and taste in a field by acquiring, as a harvest-time grain measurement data set, the yield and taste value of grains harvested in a specific parcel of a field, and recording this data set.